The present invention relates generally to implantable naturally derived biomaterials used to reinforce and/or regenerate native tissue.
Remodelable tissue grafts harvested as intact sheets from a mammalian source and processed to remove cellular debris advantageously retain the native structure of extracellular collagen matrix (ECM). This matrix of collagen fibers provides a scaffold to facilitate and support tissue ingrowth, particularly in bioactive graft materials, such as porcine small intestinal submucosa or SIS (Surgisis® Biodesign™, Cook Medical, Bloomington Ind.), that is processed to retain an effective level of growth factors and other constituents that stimulate angiogenesis.
While sheet-derived biomaterials advantageously retain the native structure of the collagen matrix, the use of individual sheets is not optimal for certain clinical applications, such as when repairing or reinforcing a body wall defect (e.g., a hernia). Single layer harvested sheets typically lack the requisite strength and durability when hydrated to permit fixation by suturing or other techniques and provide adequate reinforcement as the implanted collagen matrix degrades and is replaced. To address this limitation, overlapping sheets are laminated together by one of several known techniques, such as vacuum pressing, lyophlization (including press lyophilization), chemical cross-linking, etc., forming a more durable multilaminate construct comprising up to eight layers or more.
Multilaminate implantable ECM grafts have been demonstrated to be effective for clinical applications such as hernia repair, eliminating some of the complications associated with permanent polymeric surgical meshes, which are not resorbed by body. One potential issue with these multilaminate constructs is that the bonded layers can sometimes partially delaminate during handling after hydration, which can make the graft more difficult to suture into place. Furthermore, the separating layers of sheet material can provide pockets for the formation of a seroma, which can inhibit the remodeling process.
There remain needs for improved and/or alternative method of forming a multilaminate graft material. The present invention is addressed to those needs.